Frank Blankenship took a long drag from his electronic cigarette, breathing out a barely-visible plume of vapor that quickly dissipated into the air. Blankenship said he permanently switched to the nicotine-inhalation devices in December after being a pack-a-day cigarette smoker for 25 years.

“I can’t tell you right now that this is a stop-smoking device, because that hasn’t been proven and the FDA hasn’t cleared it as a smoking-cessation device,” Blankenship said. “But I can tell you (about) me personally, what’s happened.”

Blankenship is not only a believer in e-cigarettes — battery-powered devices that vaporize a flavored liquid mixture of nicotine and other ingredients. He’s also been selling the devices at Lucky Ruckus E-cigs, 4117 Business Park Drive, since Memorial Day.

The relatively new devices have been touted as a safe alternative to smoking, while studies have drawn mixed conclusions about their safety and agencies in the U.S. have taken steps to regulate their sale.

The Food and Drug Administration announced in 2011 it would regulate the devices as a tobacco product. E-cigarettes could be re-classified as drugs or drug-delivery devices in the future.

A number of scientific studies have shown favorable results for the e-cigarette industry. A study published by BioMed Central Public Health in 2011 concluded a study group of cigarette smokers substantially decreased their cigarette consumption without significant side effects by using e-cigarettes, and a 2012 study published by the Society for Research on Nicotine and Tobacco concluded smokers who switch from tobacco cigarettes to e-cigarettes reduce their exposure to combustion toxicants while receiving similar levels of nicotine.

E-cigarettes still carry health risks and the devices haven’t been studied long-term, said Rob Flippin, nurse manager at Texas Oncology in Amarillo.

Flippin cited a June 2012 study published in the American College of Chest Physicians’ CHEST Journal that found e-cigarettes caused “adverse physiologic effects after short-term use that are similar to some of the effects seen with tobacco smoking.”

“I know that there’s an increase in nitric oxide (levels in e-cigarette users), which is one of the mediators that we see that brings about inflammation in the lungs,” Flippin said.

Flippin said he does not recommend e-cigarettes to patients who are trying to quit smoking, but instead encourages them to reduce daily the number of cigarettes they smoke and to see if a physician would prescribe them nicotine patches or similar stop-smoking aids. Moral support from friends, family or support groups also can help, he said.

“If they can use (e-cigarettes) as a stop-gap and they’re truly reducing every day their usage, it may be a little bit better alternative, but it’s really hard to say,” Flippin said.

Blankenship acknowledged studies haven’t proven e-cigarettes are completely free of unhealthy chemicals, but said the ingredients that make up the liquid inside the devices — such as the propylene glycol cited by the CHEST Journal study as a possible source of respiratory effects — are common ingredients in food and medical products.